1. Field of the Invention
This invention relates to a stereotactic surgical guide to be detachably coupled to a conventional ultrasonic probe for use during cryosurgery to provide a laser generated aiming beam and thereby enable the accurate placement of a cryosurgical probe for producing iceballs at a localized tissue area within the body of a patient undergoing treatment for cancer.
2. Background Art
Techniques are known by which to cryosurgically destroy cancer cells in the tissue of a patient undergoing treatment. In general, a liquid or gas cryogen is used to generate extremely low temperatures sufficient to kill malignant cells. In some cases, a cryosurgical probe penetrates the patient's tissue (e.g. the prostate, liver, breast and brain) to deliver the cryogen and thereby form an iceball adjacent to the organ to be treated.
However, the size and shape of human organs vary from one patient to the next. Therefore, a significant problem faced by surgeons who practice cryosurgery is the accurate location of the iceball within the body of the patient. For example, should an iceball be misplaced relative to a patient's prostate, there is the risk that the neighboring sphincter will become frozen leading to the possibility of incontinence. Moreover, there may be an incomplete freezing of the cancerous cells in the prostate gland or an undesirable freezing beyond the prostate and into the bladder or rectum which could cause a urethral-fistula.
Guides have been used to position a cryosurgical probe within the body of a patient. However, the conventional guides have proven to cumbersome and are known to block or impede the easy insertion of the probe. In cases where the cryosurgical probe must be flared (i.e. angled) upon entering the patient's body, access to the skin surface adjacent the point of penetration is sometimes not readily available such that a special proven design is required. As a consequence of the foregoing, the ability of the surgeon to accurately position the cryoprobe is reduced while the cost and inconvenience associated with conventional guides are increased.
Therefore, what is needed is a surgical guide by which to enable surgeons to easily, efficiently and accurately insert and position a cryosurgical probe and/or a suitable positioning needle depending upon the location, size and type of tissue to be treated so as to confine the cryogenic effect to a localized cancerous area and thereby avoid the risks and inconvenience that are associated with conventional guides and techniques.